Phase III, randomized, double-blind study of nevirapine administered to pregnant HIV-1 infected women during labor, and to their neonates between 48 and 72 hours of age. The primary endpoint is the incidence of HIV-1 transmission from mother to infant. The frequency of transmission of HIV-1 from an infected mother to her infant is estimated to be in the range of 15-40%. Evidence suggests that 3 modes of transmission occur: in utero, intrapartum, and postpartum through breast milk. Nevirapine has several properties which make it an ideal candidate antiretroviral therapy to interrupt HIV-1 transmission in the intrapartum and early post-partum period. The pharmacokinetic profile suggested that nevirapine would be rapidly absorbed and transferred to the infant in utero when given during labor and delivery. In addition, nevirapine has been shown to penetrate cell free virions and inactivate virion associated RT in situ. These characteristics have led to a hypothesis that treatment of an HIV-infected pregnant woman in labor with an oral dose of nevirapine may provide a prophylactic level of nevirapine in the infant during the time of exposure to virus in the birth canal and or maternal blood. In addition, nevirapine may inactivatte the virion associated RT present in acell free virions in the genital tract or breast milk.